When the bacteria strikes, it invades the immune system causing it to turn antibodies into proteins that attack human tissue including the heart, joints and particularly the brain.

This is known as the nervous disorder, Sydenham’s chorea, and causes the basal ganglia brain structure to inflame. When this happens, scientists believe that it could trigger obsessive thoughts and compulsive rituals, which are identical to the psychological symptoms of OCD.

The researchers from the US National Institute of Mental Health (NIH) decided to look closer at the connection between Streptococcus bacteria and a condition called Pediatric Acute-onset Neuropsychiatric Disorder Associated with Streptococcus (PANDAS).

The PANDAS condition is a sudden disease where children and teenagers develop abnormal eating behaviour and psychological symptoms. Common symptoms include extreme separation anxiety, sudden temper tantrums, bed wetting and sudden deterioration in learning abilities.

Researchers found a profound link between the two and have launched a new project to find such cases and improve diagnosis and treatment of PANDAS.

They have also invested in further research into other causes of the condition aside from the Streptococcus bacteria. This will include a follow-up study to see how well IVIG (a human antibody treatment used to block autoimmune reactions) treats the syndrome.

The study has also put together guidelines on how to spot the instigating factor, Sydenham chorea, in children.

“Parents will describe children with PANDAS as overcome by a ‘ferocious’ onset of obsessive thoughts, compulsive rituals and overwhelming fears,” Susan Swedo from the NIH study said in a statement.

“Clinicians should consider PANDAS when children or adolescents present with such acute-onset of OCD or eating restrictions in the absence of a clear link to strep.”

The NIH director, Thomas R. Insel added: “As the field moves toward agreement on this broadened syndrome, affected youth will be more likely to receive appropriate care, regardless of whether they are seen by a neurologist, pediatrician or child psychiatrist.”

According to OCD-UK, obsessive-compulsive disorder is considered the fourth most common mental illness in the world. In the UK alone, around 1.2% of the population suffers from OCD (12 in every 1,000); meaning around 741,504 people are living with the condition everyday.

There are four different types of OCD, which include checking, contamination, hoarding and ruminations (intrusive thoughts).

Checking
The extreme need to check is the compulsion, with the common checking routine including gas or electric stoves, water taps, door locks, windows, car doors, people (calling them constantly in fear of harm happening to them), re-reading words in a book over and over again and seeking constant reassurance.

Contamination
The need to clean and wash everything with the intense fear that something is contaminated and will cause harm or even death. Common contamination fears include using public toilets, shaking hands, touching door knobs and handles, eating in public places, being in a crowd, avoiding red objects and stains (in fear of contracting HIV/AIDS from blood like stains) and excessive tooth brushing.

Hoarding
This is the inability to discard useless or worn out possessions as they fear that harm will occur if they throw things away. It’s also linked to extreme emotional attachment to items.

Ruminations
This is a term that often describes obsessional intrusive thoughts. These can be anything from prolonged thinking about a question that is unanswerable. The person will dwell on the time-consuming questions and feel constantly unsatisfied and appear detached.

When it isn't OCD

According to the OCD-UK website, there are certain traits that might be incorrectly labeled as OCD: “Compulsive behaviour such as, compulsive liars, compulsive shoppers, compulsive gamblers or compulsive sexaholics are other examples of something that is not part of OCD, they are more likely to be addictive problems and are considered to be Impulse Control Disorders.

The same applies to Obsessive Compulsive Personality Disorder. “Obsessive Compulsive Personality Disorder (OCPD) and Obsessive-Compulsive Disorder (OCD) sound the same, and are often confused and mistakenly interchanged as being the same illness, but the two illnesses are quite different. OCD is an anxiety disorder; OCPD is a personality disorder.”